Section: OCFS2 Manual Pages (8)
Updated: January 2012
tunefs.ocfs2 - Change OCFS2
file system parameters.
] [-J journal-options
] [-L volume-label
] [-N number-of-node-slots
] [-Q query-format
tunefs.ocfs2(8) is used to adjust OCFS2 file system parameters on disk.
The tool expects the cluster to be online as it needs to take the appropriate
cluster locks to write safely to disk.
Change the volume UUID (auto-generated) and the label, if provided, of a cloned OCFS2 volume.
This option does not perform volume cloning. It only changes the UUID and label on a cloned
volume so that it can be mounted on the node that has the original volume mounted.
Turn specific file system features on or off. tunefs.ocfs2(8) will attempt to enable or disable the feature list provided. To enable a feature, include it in the list. To disable a feature, prepend no to the name. For a list of feature names, refer to mkfs.ocfs2(8).
- -J, --journal-options options
Modify the journal using options specified on the command-line. Journal options are comma separated, and may take an argument using the equals ('=') sign. For a list of possible options, refer to mkfs.ocfs2(8).
- -L, --label volume-label
Change the volume label of the file system. Limit the label to under 64 bytes.
- -N, --node-slots number-of-node-slots
Valid number ranges from 1 to 255. This number specifies the maximum number of
nodes that can concurrently mount the partition. Use this to increase or
decrease the number of node slots. One reason to decrease could be to release
the space consumed by the journals for those slots.
- -S, --volume-size
Grow the size of the OCFS2 file system. If blocks-count is not
specified, tunefs.ocfs2(8) extends the volume to the current size of
- -Q, --query query-format
Query the file system for its attributes like block size, label, etc. Query formats are modified
versions of the standard printf(3) formatting. The format is made up of static strings (which may
include standard C character escapes for newlines, tabs, and other special characters) and
printf(3) type formatters. The list of type specifiers is as follows:
- B Block size in bytes
- T Cluster size in bytes
- N Number of node slots
- R Root directory block number
- Y System directory block number
- P First cluster group block number
- V Volume label
- U Volume uuid
- M Compat flags
- H Incompat flags
- O RO Compat flags
- -q, --quiet
- -U, --uuid-reset[=new-uuid]
Reset the volume UUID of the file system. If not provided, the utility will auto
generate it. For custom UUID, specify in either the plain (2A4D1C581FAA42A1A41D26EFC90C1315)
or the traditional (2a4d1c58-1faa-42a1-a41d-26efc90c1315) format. Users specifying
custom UUIDs must be careful to ensure that no two volumes have the same UUID. If more
than one file system were to have the same UUID, one is very likely to encounter erratic
behavior, if not, outright file system corruption.
- -v, --verbose
- -V, --version
Show version and exit.
- -y, --yes
Always answer Yes in interactive command line.
- -n, --no
Always answer No in interactive command line.
Backs up the superblock to fixed offsets (1G, 4G, 16G, 64G, 256G and 1T)
on disk. This option is useful for users to backup the superblock on volumes
that the user either explicitly disallowed while formatting, or, used a
version of mkfs.ocfs2(8) (1.2.2 or older) that did not provide this
Lists the files having holes. This option is useful when disabling the sparse feature.
Updating on-disk cluster information to match the running cluster. Users looking to
update the on-disk cluster stack without starting the new cluster should use the
During resize, tunefs.ocfs2(8) automatically determines the size of the given
device and grows the file system such that it uses all of the available space on
the device. This optional argument specifies that the file system should be
extended to consume only the given number of file system blocks on the device.
# tunefs.ocfs2 -Q "UUID = %U\nNumSlots = %N\n" /dev/sda1
UUID = CBB8D5E0C169497C8B52A0FD555C7A3E
NumSlots = 4
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